In the usual systems used for distributing either warm or cool air from a blower into a room, a series of ducts extend from a main duct and terminate in the ceiling of individual rooms. It is the usual practice to connect one or more fixed opening air outlets to the branch ducts to divert into the branch ducts by means of dampers in the main duct an amount of air required by the outlets attached to the branch ducts.
These dampers create turbulence in the ducts and render the system less efficient. The air impinging on these dampers often causes air noises and rattles which are obnoxious. Further the dampers cannot be readily adjusted if they are incorrectly set on installation. Another difficulty is that sometimes the necessary dampers are omitted entirely during installation of the system and it is an expensive procedure to install them at a later date. A substitute for such dampers is to provide the needed dampening controls at the outlet to each room.
Difficulty is also encountered in controlling air flow along walls or other surfaces through which the undesirable heat transfer is occurring. In order to blanket these walls with conditioned air, the air being supplied to the room must lose perceptible velocity as it reaches the wall in order, to prevent objectionable drafts. This requires a fine control of velocity of the air and is almost impossible to attain unless the air velocity can be adjusted after installation is made. Since the proximity of the outlet in the room to adjacent walls or other surfaces through which heat transfer is occurring is, to some extent, dependent upon the installation contractor, it is desirable to be able to control air velocity at the outlet and in all directions from the outlet.
It is also desirable to independently adjust the total volume of air flowing through an outlet as well as the amount of air flowing in one of four directions emanating from the outlet and disposed at substantially ninety degree angles to each other. Apart from these features, it is also desirable to present within the conditioned space a distributor that has a simple and attractive appearance so as to avoid undue attention to the distributor from the occupants in the space.